Nth Digit LeetCode solution in JavaScript

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var findNthDigit = function (n) {
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  var len = 1;
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  var range = 9;
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  var base = 1;
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  while (n > len * range) {
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    n -= len * range;
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    range *= 10;
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    base *= 10;
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    len++;
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  }
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  // [100, 101, 102,...]
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  // 100 should have offset 0, use (n-1) to make the counting index from 0-based.
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  var num = base + Math.floor((n - 1) / len);
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  var s = num.toString();
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  return parseInt(s[(n - 1) % len]);
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};